1. Field of Invention
The present invention relates to a projection display device and more particularly to a projection display device having a projection angle adjusting mechanism disposed in a housing case.
2. Description of Related Art
Hitherto, projection display devices are known which magnify and project optical images onto a projection screen, the images being formed by optically processing a beam from a light source corresponding to image information. These projection display devices are widely used for multimedia presentations on such occasions as meetings, academic meetings, and expositions, and may be provided in a meeting room for a presentation and the like.
The projection display device is placed on a set-up surface with the projecting lenses of the device directed toward a screen and the like. In order to adjust a projection angle with respect to the set-up surface, a projection angle adjusting mechanism is provided at the projection lens side end of the lower portion of the device.
Among conventional projection angle adjusting mechanisms, there are screw types and rack types. The former may consist of a nut member which is exposed at the bottom end, the portion from the center to the upper end of the bottom end being accommodated within the device, and a bolt member which is screwed into the bottom end of the nut member and which abuts the set-up surface at the bottom end as well. The latter may consist of a vertically movable rack member displaceably accommodated within the device with a leg portion disposed at the bottom end of the rack member to abut the set-up surface and a fixing member for fixing the rack member at a predetermined elevation.
In the screw type projection angle adjusting mechanism described above, since the nut member is accommodated within the device in a vertically extending state, a space for accommodating the projection angle adjusting mechanism in the device is required. The bolt member is required to have a large diameter to support the weight of the entire device, and a long length so as to be adjustable over a large angle range. Therefore, the nut member into which the bolt member is screwed is large, corresponding to the size of the bolt member, resulting in the need for a large space for the projection angle adjusting mechanism within the device. This inevitably causes the device to be large in size and thick.
In the rack type adjusting mechanism, since the rack member is vertically displaceably accommodated within the device, and since the fixing member for fixing the rack member is also accommodated within the device, a space within the device for disposing the projection angle adjusting mechanism is required. In particular, the rack member, similarly to the bolt member, is required to have a large thickness to support the weight of the entire device and a long length so as to be adjustable over a large angle range. This inevitably causes the device to be large in size and thick.
It is an object of the present invention to provide a projection display device capable of having a small size and which may be thin.
Accordingly, the present invention has been made to accomplish the above-mentioned object by independently disposing a projection angle adjusting mechanism conventionally accommodated within the device on an outer surface of an outer case, the projection angle adjusting mechanism. More specifically, according to the present invention, a projection display device placed on a set-up surface for projecting images formed by an optical system onto a projection screen may consist of an outer case with at least one surface opposing the set-up surface and a projection angle adjusting mechanism disposed on the outer case that adjusts a projection angle by changing an angle of the outer case with regard to the set-up surface. The projection angle adjusting mechanism is independently mounted on a surface of the outer case opposing the set-up surface.
According to the present invention, when the projection display device is placed on a set-up surface such as a desk surface, the projection angle adjusting mechanism disposed on a surface of the outer case opposing the set-up surface, that is, the bottom surface of the outer case, is maintained at a predetermined straddling angle.
According to the present invention, since the projection angle adjusting mechanism is disposed on the opposing surface of the outer case, a space for accommodating the projection angle adjusting mechanism within the device can be omitted. Therefore, reduction in projection display device space can be obtained, resulting in a device that may be small in size and thin.
In a projection display device according to the present invention, the projection angle adjusting mechanism may be detachably attached to the surface of the outer case opposing the set-up surface. Since the projection angle adjusting mechanism is independently mounted on the outer case in this configuration, it can be detachably attached to the outer case after assembling the body of the projection display device including the outer case to facilitate part replacement.
The projection angle adjusting mechanism may preferably consist of a hinge member pivotable with respect to the opposing surface of the outer case, and a fixing device that fixes the hinge member at a predetermined straddling angle thereof with respect to the opposing surface. Since the projection angle adjusting mechanism may consist of a hinge member in this configuration, it can be easily accommodated on the opposing surface (the bottom surface) of the outer case.
The hinge member may further consist of a first plate member and a second plate member rotatably fixed to the first plate member, and the fixing device may preferably consist of a moving member which moves corresponding to an open-and-closing motion of the hinge member and a retaining member that retains the first plate member and the second plate member at a predetermined straddling angle by fixing the moving member at a predetermined position. In this configuration, the projection angle can be set as desired by causing the first plate member and the second plate member to straddle each other. Moreover, the projection angle can be easily and securely fixed by changing the fixed position of the retaining member relative to the moving member, which are disposed in these plate members.
A projection display device according to the present invention may also preferably consist of a lever mechanism retained by the retaining member and for releasing the retention. In this configuration, the retention for the moving member by the retaining member and the release can be easily performed using the lever mechanism.
The lever mechanism may preferably consist of a plurality of operating portions for the retention by the retaining member and for releasing the retention, the retention being performed by at least one of the operating portions. In this configuration, the retention and release operations can be easily performed by grasping at least one of the plurality of operating portions.
In the retaining member, a plurality of grooves may further be formed, while a plurality of grooves may also be formed in the moving member portion in contact with the grooves of the retaining member, a pitch of the grooves formed in any one of the retaining member and the moving member may preferably be a plurality of times as large as that of the other. In this configuration, when the direction of the grooves of the retaining member or of the moving member even slightly deviates, the retaining member and the moving member can be smoothly engaged with each other.
In a projection display device according to the present invention, the projection angle adjusting mechanism may be preferably formed such that an inclined angle is adjustable by rotation about an axis in a direction that projecting images are projected toward the projection screen. In this configuration, even when the projection display device is inclined with respect to the set-up surface, the projection display device can be maintained in a stable position by adjusting the inclination of the projection angle adjusting mechanism itself.
The projection angle adjusting mechanism may preferably consist of an elastically deformable plate member having two ends, the plate member being axially supported at the two ends by the outer case such that a supporting shaft axis is in a direction that projecting images are projected toward the projection screen. In this configuration, the inclination of the projection display device can be easily adjusted by forcible elastic deformation of the plate member.